1. Field of the Invention
The present invention relates to a master cylinder device for a brake, which is equipped in a vehicle such as a motorcycle or an automobile. More particularly, the present invention relates to a master cylinder device for a brake which is capable of increasing an operation force to smoothly open and close a caliper that seizes a disc rotor with brake pads.
2. Description of the Related Art
In general, a master cylinder device for a rear brake of a motorcycle is comprised of a reserve tank for feeding hydraulic fluid and a master cylinder body which are independently provided and connected to each other through a rubber brake hose. Japanese Patent No. 2545224 describes such prior art.
As disclosed in Japanese Utility Model Application Publication No. Hei. 3-2962 or Japanese Laid-Open Patent Application Publication No. Hei. 10-236374, a master cylinder device for a front brake is configured such that a reserve tank is provided integrally with an upper portion of a master cylinder body that is laterally elongate, and a piston inside the master cylinder body is horizontally movable by a brake lever operated by a driver. The master cylinder body and the brake lever are mounted horizontally to a handle bar.
Japanese Laid-Open Patent Application Publication No. 2000-255409 discloses another prior art master cylinder device. In this master cylinder device, a longitudinally elongate reserve tank for feeding hydraulic fluid for a brake is provided integrally with a master cylinder body and placed such that its longitudinal axis is substantially parallel to a longitudinal axis of the master cylinder body. Inside the reserve tank, a longitudinally elongate bag-shaped diaphragm, and a fluid separator having a plurality of small-hole passages, are provided. The diaphragm communicates with ambient side and is expanded/contracted according to a pressuring force inside the reserve tank.